Fuse for ballistic missile



April 5, 1960 K. E. w. HJELM ETAL 1 FUSE FOR BALLISTIC mssm 3 Sheets-Sheet 1 Filed May 11, 1956 uvmvrons KARL ERIK WALDEMAB HJELM NILEERIK GUSTAF KULLER Al I 1414. JIW/l/l/JJ. t

Arrows April 5, 1960 K. E. w. HJELM ETAL FUSE FOR BALLISTIC mssm:

3 Sheets-Sheet 2 Filed May 11, 1956 FIG. 5

FIG. 6

HVVENTURS KARL ERIK WALDEMAB HJELM NILS-ERIK GUSTAF KULLER Anoawvs K. E. W. HJELM ETAL FUSE FOR BALLISTIC MISSILE April 5, 1960 3 Sheets-Sheet 3 Filed May 11, 1956 IN V EN TORS KARL ERIK WALDEMAR HJELM NlLg ERlK GUSTAF KULLER HM Owl! W Ar'romsvs United States Patent FUSE FOR BALLISTIC MISSILE Karl Erik Waldemar Hjelm, Bofors, and Nils-Erik Gustaf Kiiller, Karlskoga, Sweden, assignors to Aktiebolaget Bofors, Bofors, Sweden, a corporation of Sweden Application May 11, 1956, Serial No. 584,312

13 Claims. (Cl. 102-73) The present invention relates to fuses forballistic missiles, and more particularly to a percussion and impact responsive fuse for an explosive projectile.

With fuses as heretofore known, the impact responsive part of the fuse can be activated only if the nose of the fuse strikes the tar-get or in other words, if the target is hit at an angle of not much less than 90. In the event that the projectile strikes the target at a substantial slant, that is, with a part other than. the nose, the fuse cannot initiate the detonation of the projectile and the projectile glances off the target, or in any event will not cause the desired destruction thereof.

One object of the present invention is to provide a panel and improved fuse of the general kind above referred to, the design of which materially increases the probability of the detonation of a projectile striking a target.

Another object of the present invention is to provide a novel and improved fuse of the general kind above referred to, which allows a much wider latitude for the angle of impact between the projectile and the target within which the detonation of the projectile is initiated than fuse designs as heretofore known.

Still another object of the invention is to provide a novel and improved fuse which will initiate the detonation of the projectile even though the nose end of the projectile does not come in directcontact with the target.

A further object of the invention is to provide a novel and improved fuse which will initiate the detonation of the projectile not only when the nose end of the projectile strikes the target, but also when the projectile hits the target sidewise.

Other and further objects features and advantages of the invention will be pointed out hereinafter and set forth in the appended claims forming part of the application.

In the accompanying drawing several embodiments of the invention are shown by way of illustration and not by way of limitation.

In the drawing:

Fig. 1 is an isometric view, partly in section, of a fuse according to the invention.

Fig. 2 is a fragmentary view of Fig. 1 at the moment of striking a target on an enlarged scale.

Fig. 3 is an isometric view, partly in section, of a modification of the fuse according to the invention.

Fig. 4 is an isometric view, partly in section, of still another modification of a fuse according to the invention,

Fig. 5 shows the effect of a sidewise impact upon the fuse in an intermediate stage.

Fig. 6 is an isometric view of the fuse of Fig. 4 at the moment the detonation of a projectile is initiated by the fuse.

Fig. 7 is an isometric view, partly in section, of a further modification of a fuse according to the invention, and

Fig. 8 is an isometric view, partly in section, of a still further modification of the fuse according to the invention.

Referring first to Figs. 1 and 2 in detail the exemplified fuse comprises a cylindrical part 1 the upper part 2 of which is externally threaded for the purpose of screwing the fuse in the forward end of the casing of an explosive projectile. The main body of the fuse is generally conical and transversely divided in a forward or nose part 4 and a rear part 3 preferably integral with cylindrical part 1. An axial bore 5 extends through forward part 4 and rear part 3. The part of the bore 5 in front part 4 which is adjacent to the juxtaposed surfaces of parts 3 and 4 is widened and threaded at 6 to receive the upper threaded end of a sleeve 7 which is slidable in the lower part of bore 5 which is also widened to provide space for a coil spring 8 which is confined in loaded condition by a collar or flange 9 extending from the lower end of sleeve 7. Sleeve 7 is weakened at the point at which it passes from one part into the other by suitable means for instance, an annular groove 10. Bore 5 is widened at the nose end of part 4 to provide space for a small disc 11 which is joined to a rod 12 extending within the bore. Rod 12 is met at the juxtaposed surfaces of parts 3 and 4 by a rod 13 which preferably ends in a striker point coacting in a conventional manner with the ignition compound of the fuse. The lower part of rod 13 is widened to form a collar 13a against which abuts the lower end of sleeve 7.

The fuse as hereinbefore described, operates as follows:

Let it first be assumed that the nose end of the fuse hits the projectile more or less squarely. Due to the impact disc 11 will be forced inwardly. The movement of the disc is transmitted through rod 12 to rod 13 which will initiate the detonation of the projectile in a conventional manner. In other words, the fuse functions in the manner of a standard fuse.

Let it now be assumed that the fuse strikes a target indicated at 14 in Fig. 2 more or less sidewise, that is, in a direction slanted relative to the longitudinal axis of the fuse and the projectile. An impact in such direction cannot impart to disc 11 the aforedescribed rearward movement, but it will exert a laterally directed strong force upon the fuse. As a result, front part 4 jointed to rear part 3 by the weakened sleeve 7 only will break off as is indicated in Fig. 2. The upper part of sleeve 7 being removed, the remaining lower part of the sleeve can no longer restrain spring 8 and the latter will force the remainder of the sleeve downwardly. This movement is transmitted through collar 13a to rod 13 which as a result initiates the detonation of the projectile in the same manner as previously described. Fig. 2 shows rod 13 and the attendant parts in the downward position.

The arrangement according to Fig. 3 is similar to that according to Figs. 1 and 2 except that spring 8 is omitted. The required rearward movement of sleeve 7 and with it of the striker rod 13 are attained by the impact experienced by rear part 3 when the same penetrates into the target, or at least strikes against the same after the forward part has been broken off.

The fuse according to Figs. 4, 5 and 6 employs the same principle as the previously described fuse and components corresponding in function but different in structure are designated in these figures by the same reference numerals though primed.

Parts 3' and 4 of Figs. 4 through 6 are severably joined by a suitable number of screws 15 and 16 the shaft of which is weakened by an annular groove 17 or other suitable means.

The central bore 5' receives in part 4 rod 12 and in part 3 a rod 13' ending in a collar 13a. Rod 13' is held in its inactive position as shown in Fig. 4, when parts 3' and 4 are joined by means of a locking device. This locking device comprises a sleeve 18 the lower part of which is flanged at 18a. The inner wall of the sleeve is threaded at 19 and receives the upper end of a second sleeve 20. Sleeve 20 slidably receives rod 13' and is encompassed by a spring 21 the upper end of which bears aga nst flange 18a and the lower end of which abuts against the upper end of a third sleeve 22 encompassing the lower end of sleeve 20. Sleeve 23 has in its inner wall a circumferential groove 23 and sleeve 20 has two holes through its wall. Balls 24 and 25 respectively, are caged in these holes and engage corresponding indentations in a collar 26 secured to rod 13. A spring 27 encompassing rod 13' and disposed within sleeve 20 abuts Wlth its lower end against collar 26 and with its upper end against the bottom wall of sleeve 20.

l The fuse as hereinbefore described, operates as folows:

In the event the nose end of the fuse hits the target, the fuse will function in the conventional manner as described in connection with the previous figures, and in the event the fuse hits the target at a slant, part 4 will become separated from part 3' due to the weakened portion of screws 15 and 16.

Upon separation of part 4 from part 3', sleeve 18 which was retained flush with the upper surface of part 3' by the pressure of part 4 now removed, is no longer restrained and pushed upwardly by the action of spring 21 until it comes to rest by engagement of a shoulder with a corresponding shoulder formed in body part 3'. Sleeve 18 now occupies the position shown in Fig. 5. Sleeve 20 threaded into sleeve 18 follows the upward movement of sleeve 18. As a result, balls 24 and 25 are lifted into registry with groove 23 in sleeve 22 and will become disengaged from collar 26. Consequently, the collar and with it rod 13' are no longer restrained. Spring 27 is now free to move collar 26 downwardly and with it rod 13' through collar 13'a thereby initiating the detonation of the projectile.

. The fuse according to Fig. 7 may be visualized as havmg a machanism similar to that described in connection with Figs. 4 to 6 except that screws 15 and 16 for joining the two parts of the fuse body are omitted. Parts 3 and 4 are severably joined by means of an adhesive layer adhering to both parts. The layer need not be a coherent layer but several separate adhesive areas may be provided. The upper part 4 of the fuse body will be broken away from the lower part 3 in response to a slanted lmpact upon a target, and the fuse will be set off as has been described for the fuse according to Figs. 4 through 6.

The fuse shown in Fig. 8 may also be visualized as having the same mechanism as the fuse according to Figs. 4 through 6. The two parts of the fuse body are severably joined by a band 29 encircling the fuse body and over-lapping the parts 3 and 4 thereof. Band 29 which IS preferably made of metal, is retained on parts 3 and 4 by any suitable means such as circular grooves 30 and 31 engaged by appropriate indentations or benbover marginal portions of the band.

Instead of using a metal band an adhesive band such as adhesive tape may, of course, also be used.

Band 29 permits by tearing or otherwise yielding a separation of the two parts 3 and 4 in response to a slanted impact of the target.

While the invention has been described in detail with respect to certain now preferred examples and embodiments of the invention it will be understood by those skilled in the art after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended, therefore, to cover all such changes and modifications in the appended claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A fuse for an explosive ballistic missile comprising, in combination, a main body portion having a forward part and a rear part, frangible means securing said forward and rear parts of said main body portion together, said frangible means being severable in response to impact of said forward part at an angle to the longitudinal axis of said main body portion, igniting means within said rear part of said main body portion for initiating the detonation of the missile, first activating means slidably carried by said main body portion for movement between an inactive and a firing position to activate said igniting means in response to an axially directed force upon the front of said forward part of said main body portion, second activating means slidably carried by said rear part of said main body portion for movement between an inactive and a firing position, retaining means releasably securing said second activating means in said inactive position, driving means acting upon said second activating means forcefully effecting movement thereof to said active position in response to a release of said retaining means, and means for releasing said retaining means in response to the separation of said forward and rear parts of said missile.

2. A fuse according to claim 1 and further comprising spring means within the rear part of the fuse body biasing said second activating means into the position activating said igniting means.

3. A fuse according to claim 1, said frangible means including screw means extending into and between said two parts and having a weakened portion situated between the two parts and breakable in response to a slanted impact.

4. A fuse according to claim 1, said frangible means comprising an adhesive layer adhering the two parts to each other but severable in response to a slanted impact.

5. A fuse according to claim 1, said frangible means including a band encircling the two parts for joining the same and adapted to yield in response to a lateral impact thereby separating the two parts.

6. A fuse according to claim 1, wherein said second activating means comprise a sleeve slidable in the rear part coaxially with the longitudinal axis of the sleeve body, said sleeve having a rear end coacting with said igniting means for activating the same by a rearward movement of the sleeve and the forward end of the sleeve extending into the forward part secured thereto and having said weakened portion whereby upon separation of the two parts of the fuse body the portion of the sleeve in the rear end is released for activation of the ignition means.

7. A fuse according to claim 6, wherein said first activating means comprise a rod slidably disposed for movement inwardly of said sleeve, said rear part of said main body portion having a surface in facing engagement with said forward part of said main body portion, one forward end of the rod being substantially flush with said surface of said rear part, the rear end of said rod being engageable with said ignition means, and means for axially displacing said rod into activating engagement with said igniting means in response to an impact upon the nose end of the fuse body.

8. A fuse according to claim 7, wherein said rod includes a forwardly facing abutment in driven engagement with said rear end of the sleeve for effecting movement of said rod into engagement with the igniting means in response to a rearward movement of the sleeve upon separation of the two parts of the fuse body.

9. A fuse according to claim 8, wherein said displacing means of the first activating means comprise a second rod slidable within the forward part and abutting against the rod in the rear part at a point between said two parts of the fuse body, said second rod being displaceable by an impact upon the nose end of the forward part and transmitting said displacement to the first rod.

10. A fuse according to claim 9, wherein yieldable means within the rear part of the fuse body bias said sleeve toward said igniting means upon release of the sleeve by separation of the two body parts, said rearward movement of the sleeve effecting engagement of the first rod with the igniting means for activating the latter.

11. A fuse for an explosive ballistic missile, comprising a fuse body divided in a forward part and a rear part, joining means joining said two parts, said joining means being separable in response to an impact in a direction slanted relative to the longitudinal axis of the fuse body, igniting means in the rear part, first activating means c0- acting with said igniting means for activating the latter in response to an impact upon the nose end of the forward part, second activating means biased into coaction with the igniting means for activating the latter, and locking means for locking the second activating means in the rear part, said locking means being released for releasing the second activating means in response to a separation of the two parts.

12. A fuse according to claim 11, wherein said locking means comprise a movable locking member spring biased into a release position and retained in the locking position by abutment between the forward part and the rear part whereby upon separation of the forward part from the rear part said locking member moves into the release position.

13. A fuse according to claim 12, wherein said first activating means comprise a movable actuating member in the rear part coacting with said igniting means for activating the said means, said member being responsive to an impact upon the nose end of the front part, and wherein said second activating means comprise a movable actuating member coacting with the actuating member of the first activating means for biasing the latter into the posiion activating the igniting means independently of an impact upon the nose end, said actuating member of the second activating means being retained by said locking member and released for the purpose aforesaid upon release of the locking member.

References Cited in the file of this patent UNITED STATES PATENTS 

